internal/pkg: standardise artifact IR

This should hopefully provide good separation between the artifact curing backend implementation and the (still work in progress) language. Making the IR parseable also guarantees uniqueness of the representation.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/testdata/main.go

@@ -142,12 +142,12 @@ func main() {
 	}
 
 	const checksumEmptyDir = "MGWmEfjut2QE2xPJwTsmUzpff4BN_FEnQ7T0j7gvUCCiugJQNwqt9m151fm9D1yU"
-	ident := "LRxdkRYNKnZT6bKiu5W8ATeAAmq3n_5AAJkF6G0EpAOEloiZvADJBkfixgtgF1Z9"
+	ident := "dztPS6jRjiZtCF4_p8AzfnxGp6obkhrgFVsxdodbKWUoAEVtDz3MykepJB4kI_ks"
 	log.Println(m)
 	next := func() { m = m.Next; log.Println(m) }
 
 	if overlayRoot {
-		ident = "UB9HPeMgMPJf3Ut4jLWwnCtu_P3Lr29i8Erf084bHe8jjzBMKPDNxQ3RMrirkH6H"
+		ident = "RdMA-mubnrHuu3Ky1wWyxauSYCO0ZH_zCPUj3uDHqkfwv5sGcByoF_g5PjlGiClb"
 
 		if m.Root != "/" || m.Target != "/" ||
 			m.Source != "overlay" || m.FsType != "overlay" {
@@ -165,7 +165,7 @@ func main() {
 				log.Fatal("unexpected artifact checksum")
 			}
 		} else {
-			ident = "g6gj2JWNXN-oNikou626vDqcMeZCn_TcV4xKuizBaPAWcasG2sVvItb5kZovMrzE"
+			ident = "p1t_drXr34i-jZNuxDMLaMOdL6tZvQqhavNafGynGqxOZoXAUTSn7kqNh3Ovv3DT"
 
 			lowerdirsEscaped := strings.Split(lowerdir, ":")
 			lowerdirs := lowerdirsEscaped[:0]
@@ -194,7 +194,7 @@ func main() {
 		}
 	} else {
 		if hostNet {
-			ident = "TAspufRsG2I_TsxUUj2b7bUnCHgcVSdh6aOZpzL0W5Bjn4EZmOGzjofaOWd8J11H"
+			ident = "G8qPxD9puvvoOVV7lrT80eyDeIl3G_CCFoKw12c8mCjMdG1zF7NEPkwYpNubClK3"
 		}
 
 		if m.Root != "/sysroot" || m.Target != "/" {
@@ -213,14 +213,14 @@ func main() {
 	}
 
 	if promote {
-		ident = "ywzI31S5McuYu7vzI2kqpSC_nsNzpWBXVCwPoLAYi9QVT0mODgzqoo9jYYaczPbf"
+		ident = "xXTIYcXmgJWNLC91c417RRrNM9cjELwEZHpGvf8Fk_GNP5agRJp_SicD0w9aMeLJ"
 	}
 
 	next() // testtool artifact
 
 	next()
 	if overlayWork {
-		ident = "Fud5ldJfpsgLt-rkLWrLO-aVYhQm-esTswetjxydPeQMK4jHNJ_1fGHVahaiCZ9y"
+		ident = "5hlaukCirnXE4W_RSLJFOZN47Z5RiHnacXzdFp_70cLgiJUGR6cSb_HaFftkzi0-"
 		if m.Root != "/" || m.Target != "/work" ||
 			m.Source != "overlay" || m.FsType != "overlay" {
 			log.Fatal("unexpected work mount entry")